Noise spectra from single DNA molecules in their natural aqueous environment at different grades of stretching are presented. A DNA molecule is anchored between two dielectric beads. One of the beads is fixed to the surface and the other is optically trapped. The stiffness of each stage is calculated and compared with the previous results to verify the presence of one and only one single molecule. The results are compared with the preceding bibliography and are focused in the study of the spectral response which is not deeply studied yet.